Intelligent light retrofit

ABSTRACT

An apparatus and method of retrofitting a light fixture are disclosed. One method includes interfacing a retrofit controller with a dimming ballast of the light fixture, connecting the retrofit controller to at least one sensor, and connecting the retrofit controller to a power supply. Another embodiment includes a light fixture retrofit controller and a separate sensor unit. The combination of the retrofit controller and a separate sensor unit are operative to provide power and dimming control of a dimming ballast of an existing light fixture. The dimming control is base on at least one of a signal sensed by the separate sensor unit and control information received from a network.

RELATED APPLICATIONS

This patent application is a continuation patent application of U.S.patent application Ser. No. 12/849,081, filed Aug. 3, 2010, which isherein incorporated by reference.

FIELD OF THE EMBODIMENTS

The described embodiments relate generally to lighting. Moreparticularly, the described embodiments relate to retrofitting a lightfixture, providing the light fixture with intelligence.

BACKGROUND

Lighting control can be used to automatically control lighting undercertain conditions, thereby conserving power. However, lighting control,specifically advanced lighting controls have not been widely adopted inthe general commercial market because the installation, setup relatedcosts and complexity have made these lighting systems prohibitivelyexpensive for most commercial customers. Additionally, if these systemsinclude intelligence, they are centrally controlled. Central control isnot as flexible.

It is desirable to have a lighting method, system and apparatus fordistributed intelligent lighting that is easy to install and is costeffective.

SUMMARY

One embodiment includes a method of retrofitting a light fixture. Themethod includes interfacing a retrofit controller with a dimming ballastof the light fixture, connecting the retrofit controller to at least onesensor, and connecting the retrofit controller to a power supply.

Another embodiment includes a light fixture retrofit controller and aseparate sensor unit. The combination of the retrofit controller and aseparate sensor unit are operative to provide power and dimming controlof a dimming ballast of an existing light fixture. The dimming controlis base on at least one of a signal sensed by the separate sensor unitand control information received from a network.

Another embodiment includes a light fixture retrofit kit. The lightretrofit kit includes a sensor unit and a dimming controller. The sensorunit includes a sensor that is operative to generate a sensed signalbase on at least one of sensed motion or light. The sensor unit alsoincludes wireless communication circuitry that is operative to maintaina wireless link with a network, and a controller that is to generatedimming control base on at least one of the sensed signal andcommunication from a network. The dimming controller includes means forreceiving the dimming control and operative to adjust a dimming controlline to a dimming ballast.

Other aspects and advantages of the described embodiments will becomeapparent from the following detailed description, taken in conjunctionwith the accompanying drawings, illustrating by way of example theprinciples of the described embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an example of a prior art light fixture.

FIG. 1B shows an example of another prior art light fixture.

FIG. 2 shows an example of light fixture that has been retrofitted toprovide intelligence.

FIG. 3 shows another example of light fixture that has been retrofittedto provide intelligence.

FIG. 4 is a flow chart that includes steps of an example of a method ofretrofitting a light fixture.

DETAILED DESCRIPTION

The described embodiments are embodied in an apparatus and method forretrofitting a light fixture. The retrofit kit allows for upgrading ofpresently existing minimal intelligent light fixtures without having tomodify existing power line and power control wiring. The retrofittedlight fixture allows for intelligent control of the light of the lightfixture. The retrofitted light fixture can be networked with otherretrofitted light fixtures allowing for distributed control of multiplelight fixtures. Additionally, embodiments of the retrofitted lightinclude network interfaces for additional or alternative light control.

FIG. 1A shows an example of a prior art light fixture 100. The lightfixture 100 includes a light 110, and a dimming ballast 120. As shown,the dimming ballast 120 receives a power input and a dimming controlinput, and provides a regulated current to the light 110.

The light 110 can be a gas-discharge lamp, which is typicallynegative-resistance device. Such devices cannot effectively regulatetheir current use. If such a device were connected to a constant-voltagepower supply, it would draw an increasing amount of current until it wasdestroyed or caused the power supply to fail. To prevent this, a ballast(such as the dimming ballast 120) provides a positive resistance thatlimits the ultimate current to an appropriate level. In this way, theballast provides for the proper operation of the negative-resistancedevice by appearing to be a legitimate, stable resistance in thecircuit.

As shown, the lighting fixture 100 has no intelligence. The lightingfixture 100 receives all lighting control, which includes power anddimming of the light of the light fixture.

FIG. 1B shows an example of another prior art light fixture 100. Thelight fixture 100 includes a light 110, a dimming ballast 120, and acontroller 130. The controller 130 is operative to receive inputs from anetwork, or directly from a dimming control input. As shown, the dimmingballast 120 receives a power input and a dimming control input, andprovides a regulated current to the light 110.

The light fixture may include a controller 130, but has no intelligenceregarding control of the light 110. That is, the network may direct thecontroller 130 as to how to control the light 110, but the controller130 does not make its own dimming control decisions. The controller 130can also directly receive dimming control, but again, the controller 130does not make its own dimming control decisions.

FIG. 2 shows an example of light fixture 100 that has been retrofittedto provide intelligence. More specifically, a ballast controller 230 hasbeen connected to the power and dimming control inputs of the dimmingballast 120. Additionally, a sensor unit 240 is connected to the ballastcontroller 230.

For an embodiment, the ballast controller 230 provides power to thesensor unit 240, and the sensor unit 240 provides control signals to theballast controller 230. This embodiment further includes acommunications link being established between the sensor unit 240 and anetwork. Rather than being connected to a network, the sensor unit canconnect to other sensor units and ballast controllers, allowing fordecentralized control of a plurality of light fixtures. For a specificembodiment, the sensor unit 240 includes at least one antenna 250 and iswirelessly linked (through, for example, BLUETOOH® or ZIGBEE®) to thenetwork, or other devices.

The wireless link can advantageously be located within the sensor unit240 rather than within the ballast controller 230 because someconfigurations include the ballast controller 230 being located within acommon metal enclosure as the light fixture 100. Locating the wirelesslink within the ballast controller could subject the wireless link toattenuation cause by the metal enclosure. By locating the antennaproximate to, but outside of the metal enclosure of the light fixture100, the quality of the wireless link can be sustained.

For an embodiment, the conductor providing power from the ballastcontroller 230 to the sensor unit 240, and the conductor(s) providingcontrol signal(s) from the sensor unit 240 to the ballast controller arelocated in a common cable. For an embodiment, the voltage provided topower the sensor unit 240 is, for example, a low-power DC voltage. Beinga low voltage, the sensor unit 240 can be connected, and re-connected tothe ballast controller by a lay-person. That is, the voltage supply islow enough that, for example, replacement of the sensor unit is safeenough that an electrician is not required to make the replacement. Foran embodiment, the sensor unit 240 is attached to a ceiling proximate tothe ballast controller 230. The cable allows for easy installation ofthe retrofit ballast controller 230 and retrofit sensor unit 240.Exemplary cables include a flat cable with a RJ-45, RJ-50 like connectorat either end. Flat cables can be desirable because that can easily slipeasily between a guide-rail and a ceiling tile of a typical industrialceiling, without requiring a hole in the tile.

Embodiments include all of the ballast control processing based on thesensed signals and any network input occurring all or partially withinthe sensor unit 240. Other embodiments include varying amount of theballast control processing occurring within the ballast controller 230.As indicated in FIG. 2, the dimming control decisions can be distributedbetween the ballast controller and the sensor unit 240.

A manual switch, dimming control or timing dimming control unit 260 canprovide manual dimming control. Dimming control can be transferred fromautomated control provided by the ballast controller 230 and the sensorunit 240, to manual control provided by the dimming control unit 260, bythe dimming control unit 260 communicating a transfer of control. Thetransfer of control can be communicated, for example, by the dimmingcontrol unit 260 cycling power supplied by the dimming control unit 260according to a predetermined sequence. For example, the predeterminedsequence can include manually power cycling by the dimming control unit260 three times within a predetermined amount of time. If the ballastcontroller 230 and the sensor unit 240 combination receives the powercycling according to the predetermined sequence (three cycles) then themanual over-ride is invoked, and the dimming control unit 260 providesmanual control until, for example, another sequence transfers dimmingcontrol back to the ballast controller 230 and the sensor unit 240combination. Once in manual mode, the sensed signals no longer influencethe dimming control.

An existing light fixture can be upgraded as shown in FIG. 2 withouthaving to modify or update existing electrical wiring and switches. Thisis very desirable because the upgrade is easy, fast and inexpensive toimplement. Once upgraded, many light fixtures can be managed withdecentralized control. Decentralized control is desirable overcentralized control because there is not a single point of failure. Apurchaser of the retrofit kits can upgrade existing light fixtures overtime.

FIG. 3 shows another example of light fixture that has been retrofittedto provide intelligence. Here again, a ballast controller 330 has beenconnected to the power and dimming control inputs of the dimming ballast120. Additionally, a sensor unit 340 is connected to the ballastcontroller 330.

For this embodiment, however, the ballast controller 330 is interfacedto a network through, for example, the power line. As before, theballast controller 330 receives power as well.

As previously described, a manual switch, dimming control or timingdimming control unit 260 can provide manual dimming control. Dimmingcontrol can be transferred from automated control provided by theballast controller 330 and the sensor unit 340 by the dimming controlunit 260 communicating a transfer of control as previously described.

For this embodiment, the sensor unit 340 does not include as muchintelligence, and the sensor unit 340 is not connected to the network.The sensor unit 340 may or may not provide dimming controls. For anembodiment, the sensor unit 340 only provides sensed signals that theballast controller 330 performs the processing in determining thedimming control. Embodiments include varying amounts of the dimmingcontrol processing occurring in the sensor unit 340 and the ballastcontroller 330 as depicted in FIG. 3.

An embodiment includes a lighting fixture retrofit kit. The retrofit kitincludes a sensor unit, a dimming controller and an electrical cable.The retrofit kit when purchased can be used to retrofit a“non-intelligent” light fixture as shown in FIG. 1, to be an“intelligent” light fixture as shown in FIG. 2. Embodiments of thesensor unit include one or more sensors. The sensors can include, forexample, a light sensor, a motion sensor and/or a temperature sensor.When functioning, the sensor is operative to generate a sensed signalbase on, for example, sensed motion, light and/or temperature. Thesensor unit additionally includes wireless communication circuitry. Whenactivated, the wireless communication circuitry is operative to maintaina wireless link (for example, Bluetooth) with a network. The sensor unitadditionally includes a controller, wherein the controller is operativeto manage communication with the network, and to generate dimmingcontrol base on at least one of the sensed signal and communication fromthe network. The dimming controller include means for receiving thedimming control from the sensor unit, and is operative to adjust adimming control line to a light ballast.

FIG. 4 is a flow chart that includes steps of an example of a method ofretrofitting a light fixture. A first step 410 includes interfacing aretrofit controller with a dimming ballast of the light fixture. Asecond step 420 includes connecting the retrofit controller to at leastone sensor. A third step 430 includes connecting the retrofit controllerto a power supply and a network.

As shown, for example, in FIG. 2, one embodiment includes the retrofitcontroller being connected to the network (or other sensors of otherlight fixtures) through the at least one sensor. As shown, for example,in FIG. 3, one other embodiment includes the retrofit controller beingconnected to the network through a power line.

For an embodiment, interfacing the retrofit controller with the dimmingballast includes breaking existing power supply and dimming controlconnections of the dimming ballast, inserting the retrofit controller,and connecting the power supply and dimming connections of the dimmingballast to the retrofit controller. Additionally, the retrofitcontroller is connected to at least one sensor comprises attaching anexternal electrically conductive line between at least one externalsensor and the retrofit controller. Existing external electrical wiringand switches can be left alone and not modified.

For an embodiment, the at least one external sensor is affixed proximateto the light fixture. For example, if the light fixture is attached tothe ceiling of a room, the at least external sensor is affixed to theceiling proximate to the light fixture.

An external electrically conductive line is connected between theretrofit controller and the at least one external sensor. For anembodiment, the external electrically conductive line provides power tothe at least one external sensor from the retrofit controller. For anembodiment, the external electrically conductive line provides controlinformation from the at least one external sensor to the retrofitcontroller.

The at least one external sensor can merely provide sensed signals, orthe at least one external sensor can include a controller, and the atleast one external sensor being wirelessly connected to a network.Additionally, embodiments include the at least one external sensorproviding dimming control information to the retrofit controller basedon at least one of sensed information and control information receivedfrom the network.

For another embodiment, the retrofit controller receiving sensedinformation from the at least one sensor, and adaptively controlling thedimming ballast based on the sensed information. The sensed informationcan include, for example, sensed light, sensed motion, or sensedtemperature, in which intelligent lighting control decisions can bemade.

If many of retrofitted intelligent light controllers are operating inconjunction, the light controllers can all be interfaced with a centralcontroller. For this embodiment, the retrofit controller can receivecontrol information through the network from a utility managerinterface. Alternatively, the light controllers can includedecentralized control, and each retrofit controller can receive controlinformation from other retrofit controllers over the network.

As previously mentioned, the connection between the retrofit controllerand the network includes a wireless link.

In some situations, it may be determined that automated control of thelight controllers is not desirable, and that the controls should bemanual. An embodiment includes providing a manual over-ride, allowingmanual input control of dimming control of the dimming ballast.

Although specific embodiments have been described and illustrated, thedescribed embodiments are not to be limited to the specific forms orarrangements of parts so described and illustrated. The embodiments arelimited only by the appended claims.

What is claimed:
 1. A method of retrofitting a light fixture,comprising: interfacing a retrofit controller with a dimming ballast ofthe light fixture; connecting the retrofit controller to at least onesensor; and connecting the retrofit controller to a power supply,wherein the retrofit controller provides low-power to the at least onesensor, allowing the at least one sensor to be electrically connected,removed and replaced without an electrician.
 2. The method of claim 1,further comprising connecting the retrofit controller to a networkthrough the at least one sensor.
 3. The method of claim 1, furthercomprising connecting the retrofit controller to a network through apower line.
 4. The method of claim 1, wherein interfacing the retrofitcontroller with the dimming ballast comprises breaking existing powersupply and dimming control connections of the dimming ballast, insertingthe retrofit controller, and connecting the power supply and dimmingconnections of the dimming ballast to the retrofit controller, whilemaintaining existing electrical switch and wiring connections.
 5. Amethod of retrofitting a light fixture, comprising: interfacing aretrofit controller with a dimming ballast of the light fixture;connecting the retrofit controller to at least one sensor; andconnecting the retrofit controller to a power; wherein connecting theretrofit controller to at least one sensor comprises attaching anexternal electrically conductive line between at least one externalsensor and the retrofit controller; and wherein the externalelectrically conductive line provides power to the at least one externalsensor from the retrofit controller.
 6. The method of claim 5, furthercomprising affixing the at least one external sensor proximate to thelight fixture.
 7. The method of claim 5, wherein the externalelectrically conductive line provides at least one of sensor and controlinformation from the at least one external sensor to the retrofitcontroller.
 8. The method of claim 7, further comprising the at leastone external sensor comprising a controller, and the at least oneexternal sensor being wirelessly connected to a network.
 9. The methodof claim 8, further comprising the at least one external sensorproviding dimming control information to the retrofit controller basedon at least one of sensed information and control information receivedfrom the network.
 10. The method of claim 1, further comprising theretrofit controller receiving sensed information from the at least onesensor, and adaptively controlling the dimming ballast based on thesensed information.
 11. The method of claim 10, wherein the sensedinformation comprises a combination of sensed light, sensed motion, andsensed temperature.
 12. The method of claim 1, further comprising theretrofit controller receiving control information from other retrofitcontrollers over a network.
 13. The method of claim 1, furthercomprising providing a manual over-ride, allowing manual input controlof dimming control of the dimming ballast utilizing an existing dimmingcontrol mechanism.
 14. A light fixture retrofit kit comprising: a sensorunit and a dimming controller; wherein the sensor unit comprises; asensor, the sensor operative to generate a sensed signal based on atleast one of sensed motion or light; a controller, the controlleroperative to generate dimming control based on at least one of thesensed signal and communication from a network; and wherein the dimmingcontroller comprises; means for receiving the dimming control andoperative to adjust a dimming control line to a light ballast.
 15. Theretrofit kit of claim 14, further comprising a flat electrical cable forproviding electrical power from the dimming controller to the sensorunit, and providing control lines from the sensor unit to the dimmingcontroller.
 16. The retrofit kit of claim 14, further comprising thedimming controller operative to identify a sequence of power cycling,and transferring dimming control to a manual switch when a predeterminedsequence of power cycling is received.